Mating-behavior studies of lizards in three southern U.S. states has revealed which females male lizards find to be the sexiest. The research, led by Tracy Langkilde at Penn State Univeristyu, provides insight into the evolution of male-female differences. This photo shows a male fence lizard with male-type bright blue "badges" outlined in black. More information is online at http://science.psu.edu/news-and-events/2013-news/Langkilde10-2013